Analysis Of Common Pathogen And Inflammatory Markers Of Children With Lower Respiratory Tract Infection In Winter And Spring

Objective: To understand the status of the etiologic spectrum of hospitalizedchildren with acute lower respiratory tract infection (ALRI) in winter andspring，provide a basis for virological diagnosis of children with ALRI inShijiazhuang and surrounding areas.Methods:84cases of children with ALRI were collected as the researchobject, who were hospitalized in the Pediatric Department, the second hospitalof Hebei Medical University from January2011to May2011, including56boys and28girls. All of the subjects were divided into three groups: group ofinfants (less than1year old) in41cases, the child care group (1to3years old)in26cases, the group of children (more than3years of age) in17cases. Allthe cases were collected the venous blood2ml for the test of nine commonrespiratory pathogen antibodies using indirect immunofluorescence the nextday of hospitalization, including the five respiratory viruses: respiratorysyncytial virus(RSV),influenza A virus (IFVA),influenza B virus (IFVB)andparainfluenza virus (PIV), adenovirus (ADV);four atypical pathogens:Mycoplasma pneumonia (MP),Chlamydia pneumonia (Cpn), Legionellapneumophila type1(LP1), Richettsia query (QFR). And we collected theperipheral blood for the test of the blood routine and high-sensitivityC-reactive protein (hsCRP). Viewed the distribution of nine kinds ofpathogens as well as its popular features related to age, sex. Divided the casesinto RSV-IgM positive group and MP-IgM positive group. Chose the caseswhich were negative but with high hsCRP as the control group. Compare thedifferences of hsCRP and white blood cells, neutrophils ratio among the threegroups.All statistical analyses were performed with statistical softwareSPSS13.0, applyed t test, rank sum test, chi-square test and so on. Dates which were normally distributed were showed as mean±standard deviation(x±s),others were showed as median (interquartile spacing). P<0.05was consideredstatistically significant.(If hsCRP<0.05mg/L, we calculated it as0.04mg/L.)Results:1Children of subjects of the84cases, the pathogen antibody waspositive in47cases, accounting for55.95%（47/84）; respiratory virus antibodywas positive in38cases, accounting for45.24%(38/84);single virus antibodywas positive in31cases, accounting for36.9%（31/84）, and RSV antibodypositive accounted for21.43%（18/84）, IFVB accounted for13.1%（11/84）,PIV accounted for2.38%（2/84）. Atypical pathogens antibody waspositive in16cases, accounting for19.05%（16/84）,all the cases were MPantibody positive, of which the single MP antibody positive was in9cases,accounted for10.71%（9/84）. The mixed infection (viral and atypicalpathogens in mixed infections) was in8cases, accounting for9.52%（8/84）,all the cases were MP merge other viral infections.2The relationship betweengender and the positive rate of the common viruses and atypical pathogen：themale children with virus-positive rate was44.64%（25/56），and the femalechildren with virus-positive rate was46.43%（13/28）, there was no statisticallydifference(P<0.05); the male children with atypical pathogen-positive rate was19.64%（18/56），and the female children with atypical pathogen-positive ratewas17.86%（5/28）, there was no statistically difference(P<0.05).3Therelationship between age and the distribution of common viruses, atypicalpathogens and mixed infection: The study of84patients, age was1.0(1.98)years, of which a minimum of43days, the biggest11-year-old. The atypicalpathogens positive rate in infant and younger children group(less than3yearsold) was7.46%(5/67), and that in children’s group was64.71%(11/17), Thechildren group atypical pathogens detection rate was significantly higher thaninfants, the difference was statistically significant(X2was1.187，P<0.05).4The RSV-IgM antibody positive rate was highest in the group of infants,51.2%, and the child care group with children group were11.54%(3/26) and11.76%(2/17), the difference was statistically significant（X2was7.207，P<0.05）;the MP-IgM antibody positive rate which was accounted for 64.7%(11/17),was higher than child group, accounted for7.46%(5/67), thedifference was statistically significant (X21.187, P <0.05). The children’sgroup of influenza B virus-positive rate was slightly higher than the other twogroups.5The hsCRP, white blood cell value, and the proportion ofneutrophils of MP-IgM positive group were lower than bacterial infectiongroup. The hsCRP, WBC value, and the proportion of neutrophils ofRSV-IgM positive group were significantly lower than the bacterial infectiongroup; these differences were statistically significant（P<0.05）.Conclusion:1Pathogens of the lower respiratory tract infection in this regionin winter and spring were mainly viruses, and single common respiratory virusinfection was mainly to respiratory syncytial virus infection, and theninfluenza B virus and parainfluenza virus. Respiratory syncytial virusinfection is more common in infancy. The infection of Atypical pathogens wasmainly Mycoplasma pneumoniae, of which the positive rate was the highest inchildren group. Mixed infection (viral and atypical pathogenicmicroorganisms mixed infection) was mainly Mycoplasma pneumoniaeassociated with other viral infections.2Respiratory syncytial virus (RSV) is the mainly pathogen in infant groupwith lower respiratory tract infections in the winter and spring in this region.Mycoplasma pneumoniae is the mainly pathogen in children group with lowerrespiratory tract infections in the winter and spring in this region. Mycoplasmapneumoniae infection can lead to blood hsCRP, white blood cells andneutrophil ratio elevated. The hsCRP, WBC value, and the proportion ofneutrophils of RSV-IgM positive group were significantly lower than thebacterial infection group.3In this study, we used indirect immunofluorescence to detect the commonnine pathogens specificial IgM antibody of respiratory. It has the advantagesof high sensitivity, good reproducibility, easy to operate, fast, and can be as early diagnosis of infection.